A wide variety of plastic material bottles are used for storing and dispensing a wide variety of chemical products such as cleaning liquids or pesticide. For applications where a concentrate solution can be housed within a smaller container and housed within the larger, ready-to-use container, or where two components must be isolated from each other before being mixed to form a ready-to-use preparation, packaging or assembly with two plastic bottles are used or envisaged. For example, U.S. Pat. No. 3,443,726 disclosed a container consisting of two container sections which are threadably engaged and are designed to be screwed into one another. This container however can only be handled as a single unit because the upper container section is only closed by insertion of the lower bottle/section with a stopper in between to prevent the mixing of the contents. U.S. Pat. No. 4,823,946 discloses an improved two-compartment container consisting of two separately Tillable bottles designed to be fitted together one above the other through an intermediate component. Although this two-compartment container can be filled and sealed independently of one another and can be stored, handled and supplied separately from and independently of one another as filled individual components, the intermediate connecting component requires a large pitch thread on the neck of the second bottle for it to be easy to use. U.S. Pat. No. 5,277,303 disclosed a two bottle packaging that further improves the intermediate connecting component of the two-compartment container of U.S. Pat. No. 4,823,946 so that the lower bottle can be made of glass instead of only plastic due to the large pitch thread required in U.S. Pat. No. 4,823,946.
All of the above two bottle packaging or assembly, however, still require complicated connecting or linking means to keep the two bottles together.